1. Field of the Invention
The present invention relates to a device and method whereby a more comfortably listenable audio signal can be reproduced by an audio signal being subjected to processing with, for example, a noise canceling system or the like.
2. Description of the Related Art
Hitherto, there has been an active noise canceling system included in headphones. The noise canceling systems currently in practical use are generally classified into two methods of a feedback method and a feed-forward method.
For example, Japanese Unexamined Patent Application Publication No. 3-214892 discloses an arrangement wherein noise within an acoustic tube 1, collected at a microphone unit 6 provided within the acoustic tube 1 mounted in the ear of a user, is subjected to phase inversion to emit sound from an earphone unit 3 provided in the vicinity of the microphone unit 6, thereby reducing external noise.
Also, Japanese Unexamined Patent Application Publication No. 3-96199 discloses an arrangement relating to noise reduction headphones wherein the output of a second microphone 3 disposed between headphones 1 and the ear canal of a user is employed at the time of mounting to identify the transfer characteristic from a first microphone 2 to the headphones 1 which collect external noise provided in the vicinity of the ear at the time of mounting with the transfer characteristic until external noise reaches the ear canal, whereby external noise can be reduced regardless of the method of wearing the headphones.
In the cases of the above-mentioned techniques disclosed in Japanese Unexamined Patent Application Publication Nos. 3-214892 and 3-96199, ambient noise is reduced, thereby adjusting a listening environment wherein audio signal to be reproduced is suitable.